Radically initiated polymerization of a methacryloylamido-terminated saccharide .1. Monomer synthesis, homopolymerization and characterizations

A methacrylamido-terminated saccharide, 6-deoxy-6-methacryloylamido-D-glucopyranose (MAG), was synthesized using a new and easy pathway. Kinetics of the radically initiated solution homopolymerization of this monomer was investigated at 50 degrees C using 4,4'-azobis(4-cyanopentanoic acid); the obtained k(p)/k(t)(1/2) value around 1.0 mol(-1/2). L(1/2). s(-1/2) is indicative of the strong ability of MAG to polymerize (k(p) and k(t) being the rate constants of propagation and termination, respectively). The chemical structure of the homopolymer, as analyzed by C-13 NMR spectroscopy shows a tacticity which is in favor of a syndiotactic configuration resulting from the bulkiness of the side group. The dimensional characteristics of the polymers were studied by light scattering as an on-line detection in size exclusion chromatography (SEC). As expected from the k(p)/k(t)(1/2) value, high weight-average molecular weights were obtained. The small average radii of gyration were found to reflect a relatively compact structure in water due to inter- and intramolecular interactions; viscosity studies in various solvents as well as values of the second virial coefficient corroborate such a behavior which reflects that water is a poor solvent for poly(MAG).